Laptop Heat May Cool Fertility, Study Finds

By Susan B. Shor
Dec 9, 2004 1:18 PM PT

Men who have been balancing laptops on their knees as they work during rush hour on the train or wait in the airport for flights may be at risk of more than aches and pains from hunching over that little keyboard. They could also be prone to another major side effect: infertility.

Dr. Yefim R. Sheynkin has found that men who balance their laptops on their laps risk infertility problems because of the combination of pressing their legs together, which constricts the scrotum, and the heat from the laptop, which raises its temperature.

Healthy Men Heat Up

Sheynkin, director of male infertility and microsurgery at the State University of New York, Stony Brook, led a study of 29 healthy men ages 21-35 using laptops. The men were wearing casual clothing and were seated in a temperature-controlled room. They were given laptops powered by Intel Pentium IV processors. The higher the clock-speed, the higher the heat, especially without recently announced power-saving cooling technologies for the chips.

The study, published in the European medical journal Human Reproduction, found that after sitting with a laptop in their laps for 15 minutes, men's scrotal temperatures had risen 1 degree Celsius (1.8 degrees Fahrenheit).

After an hour, that reached 2.8 degrees C (5 degrees F). Earlier studies have suggested that a 1 degree C increase in temperature can reduce sperm concentration as much as 40 percent.

Long-Term Effects Unknown

Sheynkin told TechNewsWorld that it is not known whether the effects of the exposure would cause permanent damage, but the study recommended that men take the laptops off their laps to avoid the potential for "irreversible changes."

"Until further studies provide more information on this type of thermal exposure, teenage boys and young men may consider limiting their use of laptop computers on their laps, as long-term use may have a detrimental effect on their reproductive health," Sheynkin said in a statement on the journal's Web site.

Fertility experts often caution men to avoid prolonged heat exposure such as intense exercise and hot tubs if they want to preserve their fertility. Studies have also found that electric blankets and heated waterbeds can reduce sperm production.

More studies are necessary to pinpoint the effects of the temperature increase, Sheynkin said.